ZF 5HP18

Transmission general data

The 5-speed ZF5HP18 transmission is related to 4-speed 4НР14 and 4HP22 units. It had been installed on RWD BMW of 3-rd,5-th and 7-th series with 2-3 liter engines since 1991 up to 1999. The ZF5HP18 unit is a predecessor of famous ZF 5HP19 for a bit less powerful engines (310 Nm in comparison with 325 Nm in 5HP19). This well-designed gear shifting solution with high reserve on transmission components, which served as a prototype of the ZF 5HP19 solution.

Technical issues and repair guidelines

This transmission endures exploitation with contaminated fluid, fluid shortage, and operation without a warm-up. This transmission will fully serve the service life, if you monitor the ATF quality and timely replace the metal-plastic filter with a felt membrane. This transmission can operate with different types of oil (works well with oils like Dexron III).Too rapid ATF contamination is a signal of gaskets wear-out and trigged by it risk of oil starvation on fiction components.

To perform a typical overhaul with reassembly of worn-out gaskets and rings repair specialists usually order the Overhaul kit for this transmission.The most vivid soft spot of the 5HP18 unit is the clutch package F – the first one to get out of order because of ATF shortage and burnt frictions.The cause of this problem is related to design of the drum F bushing with a sealing, which become the source of leakages leading to oil starvation and bushing cranking.If the abovementioned problem stays neglected, then the clutch drum F with a piston gets burnt together with frictions. This problem is solved by the bushing replacement with the bearing.

The oil pump is one more typical part to be worn-out in “old” transmission hard parts under the condition of long-term exploitation with worn-out torque converter and pump bushing.The valve body is a long-running and maintainable unit.

The pressure solenoid (EPC) is a main part to be replaced or repaired among electrical components.Shifting solenoids are similar to solenoids used in the 4HP18 unit and they serve for a long period of time. EPC solenoids are the first to get out of order, then comes the turn of the TCC solenoid. In all other respects, the resource of this transmission is compatible with the resource of the whole car.